The subtleties of the use of gypsum mixtures. Gypsum plaster: do-it-yourself perfectly smooth walls By what criteria are they evaluated

The main components of gypsum dry mixes are: gypsum binders, fillers, functional additives.

As a binder in gypsum mixtures, building gypsum based on calcium sulfate hemihydrate is used. Less often they are used in a mixture with anhydrite (especially for plastering works) to ensure the required setting time. High-strength (experts say “high-quality”) gypsum and anhydrite are used in the compositions of self-leveling mixtures. The use of these types of gypsum binders in flooring compositions is explained by the special requirements for the strength of such solutions.

The filler is introduced to reduce the cost of the product, but most importantly - to prevent cracking during operation. In addition, its use improves the manufacturability during application. As aggregates in gypsum mixtures, quartz sand is used, as well as limestone flour, dolomite flour, chalk, and ash. Perlite is used in the compositions of light plasters - for example, in mixtures such as HYPER PLAST (the name of this mixture comes from a combination of the words Gypsum and PERLITE). In certain types of putty mixtures, the use of mica is recommended. The dispersion of aggregates is determined by the type of gypsum mixture: quartz sand and limestone sand are used with a dispersion of up to 0.8-1.0 mm. When selecting aggregates, special attention is paid to the granulometric composition: there should be approximately the same ratio of aggregate fractions.

Hydrated lime Ca(OH)2 is added to gypsum mixtures to improve plastic properties, reduce shrinkage and slow setting.

Functional additives slow down the setting speed of the gypsum mixture, increase its water retention, mobility, plasticity, adhesion strength, and reduce the risk of cracking.

Setting retarders are important functional additives that provide an increase in the survivability of the gypsum mortar mixture. It is known that gypsum binders set quickly, and the solution to the problem of increasing survivability lies in the correct choice of special additives - setting retarders.

Cellulose fibers are introduced into the composition of gypsum mixtures to reduce cracking and shrinkage.

These are the lightest in weight and easy-to-work formulations. Their only drawback is the possibility of use only inside dry rooms.

Gypsum is known to be a fast-setting and hydrophilic (water-absorbing) compound. The same polymers are introduced into the gypsum-based mixture in order to reduce water absorption and increase adhesion (adhesion strength), as well as inhibitors - substances that slow down the gypsum hardening reaction. The simplest example of an inhibitor is food or technical citric acid. If, when mixed with water for 1 kg of gypsum, you add 10-20 grams citric acid, then the gypsum mass will slow down its hardening to 30-40 minutes.

Gypsum mixtures are divided into:

Gypsum putties

They consist of a gypsum binder (hereinafter we will call it gypsum, although a mixture of alpha gypsum and anhydride is used in the production), quartz or limestone filler, cellulose thickener and a redispersible polymer. Gypsum putties can be applied in layers from 1 mm to 1 cm.

Attention! Gypsum is calcium sulfate - CaSO4. When painting a surface leveled with such a mixture, it is necessary to use acid-resistant paints. And, accordingly, observe safety precautions: gypsum, even in a small wound, causes very discomfort.

Gypsum plasters

Dry mixes that have earned the highest recognition from professional builders. They are light, easy to use, do not shrink (unlike lime-sand-cement putties), quickly harden on the surface and have a fairly high performance - from 30 minutes to 1 hour.

You can make the simplest gypsum plaster in your kitchen: take 10 kg of gypsum, 1 kg of slaked lime, 50 grams of citric acid, mix it all with water and mix until a thick sour cream is obtained.

With the finished mixture, you can close up the strobes, level the wall or ceiling. Although industrially prepared plasters also contain fractionated sand, a cellulose thickener and a redispersible polymer. In some compositions, to give the plaster volume and lightness, expanded perlite or vermiculite is added - light, weightless sands. The average consumption of such a plaster is 7 kg / m2 with an application layer of 1 cm.

Gypsum-based mounting adhesives

If we want to glue a drywall sheet, mineral insulation, a foam sheet to the wall, gypsum-based mounting adhesive is best for us. The composition is similar to the composition of tile adhesive, with the exception of the main component: instead of cement, gypsum.

Gypsum floor mixes

Self-leveling (self-leveling) compositions for pouring floors in various layers. The composition and principle of action are discussed in the first part of the article (see also the article Leveling the floor).

Putties based on a polymer binder

They differ from the above types of dry mixes in that they do not contain either cement or gypsum. These are fillers, almost 100% consisting of aggregate - fine limestone or marble flour, cellulose thickener and redispersible polymer.

Putties of this type are very convenient in application and subsequent processing (sanding), suitable for subsequent painting or wallpapering. In diluted form, they have a working capacity of up to 24 hours. But these putties are not intended for leveling surfaces for laying tiles. Putties based on a polymer binder are used only inside dry rooms as a finishing layer for leveling the surface and are not used without further coating.

Dry mortar is a multi-component dry powder, which, when diluted with water, turns into a plastic solution for the desired purpose. Gypsum-based mixtures are lightweight and easy-to-work compositions. The disadvantages include only the possibility of use only inside dry rooms.

Materials based on gypsum binders are characterized by high heat and sound insulation properties, fire and fire safety, lightweight, can be used as decorative elements for architectural solutions interior decoration premises. The use of gypsum materials for interior decoration provides favorable climate indoors due to the ability of the material to "breathe" - it is easy to absorb moisture and give it away. In recent years, new generation materials based on gypsum binders have been developed: composite, modified, with reduced water demand and high performance properties.

The main components of gypsum dry mixes are: gypsum binders, fillers, functional additives. As a binder in gypsum mixtures, building gypsum based on b- or a-calcium sulfate hemihydrate is used. Less often they are used in a mixture with anhydrite (especially for plastering) to ensure the necessary setting time. In the compositions of self-levelling mixtures, high-strength gypsum (a-hemihydrate) and anhydrite are used. The use of these types of gypsum binders in flooring compositions is explained by the requirements for such mixtures and hardened mortars - the necessary vitality and high early strength, providing a short time walking.

Gypsum is a quick-setting and water-absorbing compound. Polymers are introduced into gypsum-based mixtures to reduce water absorption and increase adhesion, as well as inhibitors that slow down the gypsum hardening reaction. Inhibitors include, in particular, food or technical citric acid. If, when mixed with water, 10-20 grams of citric acid is added to 1 kg of gypsum, the gypsum mass will slow down its hardening to 30-40 minutes.

The filler is introduced to prevent cracking during operation, improve manufacturability during application. As aggregates in gypsum mixtures, quartz sand is used, as well as limestone flour, dolomite flour, chalk, and ash. Perlite is used in the compositions of light plasters. Functional additives slow down the setting of the gypsum mixture, increase water retention, mobility, plasticity, adhesion strength, create a special porous structure, and reduce the risk of cracking. Setting retarders provide an increase in the survivability of the mortar gypsum mixture. It is known that gypsum binders set quickly, and the solution to the problem of increasing survivability lies in the correct choice of special additives - setting retarders. Water-retaining additives are introduced into gypsum mixtures to increase water retention, adhesion to the base, improve mixing, and impart viscosity and plasticity to the mortar mixture. Dispersants (plasticizers) - additives that are absorbed on the surface of the particles of the mortar mixture, reducing the formation of lumps during its preparation. Pore ​​formers are additives used in plaster mixtures to create a special pore structure of the hardened material.

Gypsum mixes are divided into gypsum putties, gypsum plasters, grout mixes, gypsum-based mounting adhesives, and gypsum floor mixes.

Gypsum putties consist of a gypsum binder (we will call it gypsum, although a mixture of alpha gypsum and anhydride is used in the production), quartz or lime filler, a cellulose thickener and a redispersible polymer. Gypsum putties are applied with a layer of 1 mm to 1 cm. Gypsum putties are distinguished by high plasticity and whiteness. Used for plastering walls and ceilings inside dry rooms, with an improved and high-quality finish in the final application. Gypsum-based compositions are especially common today.

When working with gypsum mixtures, you need to know that gypsum is calcium sulfate. When painting a surface leveled with such a mixture, it is necessary to use acid-resistant paints. Do not forget about safety precautions: gypsum, even in a small wound, causes discomfort.

Gypsum plasters- dry mixes, which have gained particular popularity among builders. Mixtures are light, easy to use, do not shrink (unlike lime-cement-sand putties), quickly harden and have high performance - from 30 minutes to 1 hour. Dry plaster mixtures based on gypsum are designed for plastering walls and ceilings with different surface indoors with normal and high humidity (kitchens and bathrooms).

Simple gypsum plaster can be prepared independently. The composition (10 kg of gypsum, 1 kg of slaked lime, 50 g of citric acid) is mixed with water and mixed until the consistency of thick sour cream.

With the finished mixture, you can close up the strobes, level the walls or ceiling. Industrial plasters also contain fractionated sand, a cellulose thickener and a redispersible polymer. To give the plaster lightness and volume, light weightless sands are added to the compositions - expanded perlite or vermiculite. The average consumption of such plaster is 7 kg / sq.m when applied with a layer of 1 cm.

Gypsum-based mounting adhesives. Of particular interest are dry gypsum mixes for installation work, which are used for gluing sheet and tile materials (gypsum board, mineral insulation, foam sheets). The composition is similar to the composition of tile adhesive, only gypsum, not cement, is used as the main component.

Gypsum mixes for a floor. This group includes self-leveling (self-leveling) compositions for pouring floors in various layers. Dry mixes for self-leveling floors have a more complex composition and include such functional additives as superplasticizers, hardening accelerators, defoamers. Gypsum-based compounds are mainly used for indoor screeds.

It must meet very different requirements, sometimes almost opposite: high vapor permeability and insensitivity to water, for example. No less controversial is the desire to obtain material with low consumption and very high hiding power. However, gypsum plasters can also fulfill this condition.

- a typical sedimentary mineral based on calcium sulfate. From the point of view of finishing, the material on its base is attractive in that it creates a surface of perfect white color. No additional putty or painting under light wallpaper, for example, is required. However, that's not all distinctive features material.

The fundamental difference between decorative and leveling plasters is in the setting speed, or, more precisely, in the time until the layer remains plastic. For leveling plaster, it is desirable to reduce this period to a minimum, but for the decorative version, the opposite is true: as long as the layer retains plasticity, it can be processed with special tools to achieve a decorative effect.

Gypsum is quite suitable for both purposes, but only in the presence of polymer additives, which regulate the period of plasticity and setting time. In this case, the filler can be different, but only fine textured.

Advantages

Material advantages:

• Gypsum plaster it is very plastic, even the usual one for leveling walls can be smoothed down to a glossy sheen. Gypsum-based modulating - best material to create is not easy complex reliefs, but relief images.
• Gypsum plaster can be applied both manually and by machine: the modifiers added to the mixture regulate the mobility of the solution over a very wide range.
• Excellent White color serves as an ideal base for any decoration: coloring, image formation.
• Do-it-yourself gypsum plaster can include many additional components that noticeably change properties. So, the additive allows you to apply the mortar on concrete walls with the same ease as conventional lime mixtures. And the addition of perlite significantly enhances the thermal insulation properties of the plaster: this composition is recommended for finishing concrete walls, since the thermal conductivity of the latter is unpleasantly high and the walls feel cold to the touch.
• Vapor permeability makes it possible to classify gypsum-based finishes as the most environmentally friendly and safe coatings.
• Increased hygroscopicity can be not only a disadvantage: when poured from above, for example, a water stain, provided that the latter was clean, will disappear on its own in 2-3 days. The material not only absorbs, but also releases moisture when it is in excess.
• The consumption of the solution is 1.5 times less than that of the most economical.

disadvantages

Disadvantages of gypsum plaster:

• An obvious important disadvantage is its high hygroscopicity. The material absorbs moisture, and therefore is not used either for external work or for decorating rooms where it is provided high humidity– bathroom and kitchen, for example.
• However, the Rotband website has information on the types of gypsum plaster that can withstand dampness, but in the absence of direct contact with water. That is, for the bathroom, this option is still not good.
• For the same reason, gypsum-based decorative plasters are not washable. Maximum - dry cleaning and the use of a barely damp cloth when severe contamination appears.
• Gypsum finish does not differ in mechanical strength: you should not use sharp tools to check its integrity.
• The hardening time for gypsum plaster is too short - 50 minutes in a container before hardening. Considering that during this time it is necessary not only to apply a layer, but also to create a decorative surface, it is necessary to prepare the solution in small portions, which somewhat complicates the work.

Scope of use

The area of ​​use of HS is determined by its properties and composition.

• Living quarters - due to the high vapor permeability and environmental friendliness, it is this finish that is recommended for the nursery. On the other hand, she does not wash, so the decision of this issue depends on the owner of the apartment. In the living room or bedroom, the material is used without restrictions.
• Even the most "water-resistant" option does not tolerate direct contact with water. And if certain varieties can be used for the kitchen, then not for the bathroom.
• Gypsum leveling compounds are an excellent base for other finishes. And they are still in demand when it is necessary to create a truly snow-white surface of a wall or ceiling. The thickness of the layer can vary from 5 to 50 mm, with reinforcement - up to 70 mm. The material sets within 80–150 minutes, and dries completely in 5–7 days.
• GSh is applied to, brick wall, and even a metal surface if it is protected by an anti-corrosion agent. When finishing surfaces with high porosity - gypsum fiber, you should use a special primer. GSh is not applied to wooden surfaces: adhesion is low.
• Modeling plasters based on gypsum are used to decorate only residential premises. Images and ornaments are created in the usual way for this kind of plaster - with a stamp, a roller with a relief surface or the movement of a trowel.

Solution and its preparation

Despite the simple composition, it is recommended to work with a ready-made gypsum mixture, since those added under production conditions polymer additives significantly improve the properties of the finish. At home, such a uniform distribution of the substance cannot be achieved.

Composition and structure

The usual composition of the mixture:

• gypsum;
• fine fraction filler - with grain up to 1.5 mm;
• additional additives.

This restriction is a fine fraction, reduces the amount decorative options. In fact, only modeling plasters are obtained on the basis of gypsum. Leveling compounds are much more popular.

The solution, as already mentioned, is prepared in small portions. After 50 minutes, the mixture completely solidifies. 25-30 minutes - the period of sufficient plasticity of the material.

And now we will analyze the composition, proportions and recipe of gypsum plaster.

From this video you will learn about the technology of applying gypsum plaster on lighthouses:

Recipes

With sawdust

There are quite a few recipes for preparing the mixture - we mean leveling types:

• 1 volume fraction of a mixture of Rotband or Ecogypsum;
• 1 share of crushed sawdust;
• 3-4 shares.

The dry ingredients are mixed, and then added in small portions to the water.

The composition has good sound and heat insulation qualities.

Gypsum-chalk

Gypsum-chalk plaster is more suitable for finishing, is prepared as follows:

• crushed chalk - 3 kg;
• gypsum - 1 kg;
• 5% wood glue solution.

Gypsum and chalk are mixed, and then wood glue is added to the container with the ingredients until a pasty mass is obtained. Since the solution sets quickly - there are no modifiers here, then it should be prepared from a dry mixture little by little.

Lime-gypsum

Lime-gypsum plasters for interior decoration are even more popular: they set more slowly and better tolerate mechanical stress.

The composition is:

• water is added to 1 part of gypsum with stirring until a gypsum dough is obtained;
• 3 shares of lime are dissolved in water;
• then the solutions are thoroughly mixed.

From ready mix

• A dry mixture of gypsum plaster is poured into a container with water at the rate of 0.5–0.7 liters per 1 kg of the mixture, mixed until smooth. You can mix both manually and with the mixer attachment on a drill.
• The solution should stand for 3-5 minutes, then it is mixed again and used.

It is impossible to dilute the composition with water again. Next, the technology of applying gypsum plaster is considered.

Application technology

So, how to properly plaster walls with gypsum plaster? The solution should be applied within 30 minutes. For this, a trowel or a falcon is used - a square platform on the handle. The latter is often used when working with the ceiling.

1. The resulting solution can be applied in a layer of 10 to 50 mm, on the ceiling - 30 mm. If a thicker layer is required, then the second one should be applied only after 24 hours.
2. Align the layer with the rule.
3. After 45–60 minutes, the GSH layer is smoothed with a metal spatula or processed with a decorative tool.
4. If the surface is prepared for wallpaper or paint, then after 20 minutes, when the layer is no longer pressed through with a finger, the coating is moistened with water, and when it becomes dull, rubbed with a sponge. The movements are circular. Then the wall is smoothed with a spatula. A day later, this procedure is repeated. So get smooth surface that does not require puttying.
5. Drafts should be avoided on the first day. The coating dries completely within 5-7 days, after which you can proceed to further finishing.

About the consumption of gypsum plaster per 1 m2, read below.

The video below will tell you about applying gypsum plaster without beacons:

GS consumption

Gypsum plaster is one of the most economical coatings - this means leveling plaster. When forming a layer of 10 mm, the consumption is 10 kg per 1 sq. m.

For comparison, lime leveling plaster needs at least 14-15 kg.

Requirements for the quality of materials

The quality of dry building mixtures based on gypsum binder is regulated by GOST 31376-2008. Mixtures, ready-made mortars and the actual plaster layer are subject to verification.

Dry formulations must meet the following requirements:

• grains with a diameter of 5 mm are not included in the mixture. Granules with a diameter of 1.25 mm can be no more than 1.0% by weight, with a diameter of 0.2 mm - no more than 12% and with a diameter of 0.125 mm - no more than 15%.
• humidity of the mixture - no more than 0.3% by weight;
• the activity of natural radionuclides must comply with the requirements of GOST 30108.

Ready-to-use mixtures must fulfill the following conditions:

• setting time with a manual method - 45 minutes;
• setting time in machine production - 90 minutes;
• the ability to retain water is at least 90%;
• the mobility of the mixture must comply with GOST 31376: the diameter of the spread is 165 mm with an error of 5 mm. This indicator can be changed at the request of the customer.

The finished coating must meet the following requirements:

• ultimate strength in bending - not less than 1 MPa;
• compressive strength - not less than 2 MPa;
• adhesion strength - not less than 0.3 MPa.

If necessary, the average density of the plaster layer is also found.

Popular brands and prices

Numerous companies producing materials for building decoration did not ignore gypsum mixtures.

• The most famous in our market are gypsum plasters "Rotband" from Knauf (Knauf). It is these compositions that can be used in relatively wet rooms. It can be used for both manual and machine application. The weight of the package is 30 kg, the price of gypsum plaster is from 290 to 355 rubles.
• No less popular is the manufacturer of gypsum plaster "Volma". It is a leveling plaster with excellent adhesion for any type of surface except wood. Package weight - 30 kg. Price - from 270 to 355 rubles.
• They compete with dry gypsum mixes from Osnovit. Both white and gray gypsum plasters are produced. Package weight - 30 kg, cost - from 260 rubles.
• Under the brand name "Prospectors" a variety of Construction Materials, including gypsum plasters designed for leveling and finishing concrete, brick, and other surfaces. Package price - from 270 to 305 rubles.
• Gypsum plaster from Vetonit is designed for both manual and machine application, the cost of a package weighing 20 kg is from 394 rubles.

Gypsum plaster in the vast majority of cases belongs to the category of leveling mixtures. It is ideal for living rooms with low humidity and a stable microclimate.

This video will tell you about the use of Rotband gypsum plaster from Knauf:

10.02.2009

Gypsum dry mixes

One of critical issues building materials industry is to develop the domestic production of efficient building materials on the basis of harmonious and balanced activities in relation to environment, saving material and fuel and energy resources, maximizing the use of local and technogenic raw materials.

In this aspect, building materials and products based on gypsum binders (GB) are promising. Gypsum binders and materials based on them have a number of valuable qualities. The production of gypsum binders is non-toxic, characterized by low specific fuel and energy consumption (approximately 4-5 times less compared to cement production). Gypsum materials have good heat and sound insulation properties, fire and fire safety, relatively low density, decorative effect.

In addition, the use of gypsum materials for interior decoration provides a favorable indoor climate due to the ability of the material to "breathe", easily absorb and release moisture. Research on the development of waterproof gypsum binders has expanded the areas of their possible application. Binders of a new generation based on gypsum binders, characterized by reduced water demand and high performance properties, have been developed.

Despite the undoubted advantages of gypsum materials and products over materials based on other binders, the scale of their use in Russia is currently significantly inferior to cement-based products.

The range of gypsum binders produced in the country for construction works limited to building gypsum produced in accordance with GOST 1 25-79 with a strength range of 3 to 7 MPa.

Anhydrite binder, which is very promising due to the low cost of raw materials and low investment in processing, has not yet found sufficient distribution. Such a binder has the same positive properties as other gypsum binders, and even surpasses it in final strength. It can be used for the same purposes as gypsum binder, including for the production of dry building mixes.

Building mixes made on the basis of gypsum or anhydrite binders are called dry gypsum mixes (SGS).

A distinctive feature of mortars based on gypsum dry mixes, in comparison with cement mortars a similar purpose is the increased yield per unit mass of the dry mixture. The use of gypsum dry mixes for finishing provides a reduction in labor costs by more than 2 times, and the consumption of the mixture is almost 2 times lower than the cement mixture for the same area of ​​processing.

SGS are homogeneous bulk materials of optimal composition, consisting of carefully dosed and mixed dry components - gypsum binders, fractionated aggregates (fillers), pigments and modifying additives for various purposes.

In accordance with the existing classification, the GHS can be divided into the following main types:

plastering (including decorative and protective);

putty;

mounting;

adhesives;

grouting;

floor (leveling for flooring).

Mixtures based on non-water-resistant gypsum binders are used for interior decoration of buildings and structures with dry and normal indoor conditions, and GHS based on waterproof gypsum binders for finishing work in rooms with normal, wet and wet conditions, as well as when finishing facades of buildings in accordance with applicable regulations. regulatory documents SNiP 3.04.01-87, SNiP 2.03.13 - 88, SNiP P -3 - 79*.

Plaster gypsum mixes

Plaster mixtures are mortar mixtures from non-waterproof gypsum binders of B- or a-modifications, anhydrite or mixtures thereof, coarse-grained aggregate with a fraction of not more than 2.5 mm and special chemical additives for various purposes. Such mixtures are intended for rough leveling of surfaces by single-layer plastering of walls and ceilings with different kind surfaces (concrete, brickwork, cellular concrete, other rough and corrugated surfaces).

To the most known species gypsum plaster mixes include: ROTHBAND, GOLDBAND, GIPSPUTS HP 100, MASHI-NENPUTS MP 75, ACOUSTICPUTS, TEPLON, SILIN, FARVEST-Gypsum, GYPSUM white, GYPSUM gray, CONSOLIT 500, etc.

Gypsum plaster mixtures and solutions from them should be characterized by the following indicators:

bulk density of the mixture, kg/m3 -700...1100;

water-to-solid ratio (the amount of mixing water required to obtain a given mobility of the solution) -0.5 ... 0.b;

solution processing time, min. -50...100;

hardened mortar density, kg/m3 -800...1100;

compressive strength, MPa - 2.5 ... 7.0;

tensile strength in bending, MPa - 1.5 - 3.0;

adhesion strength with the base (surface to be treated), MPa - 0.4 ... 0.7;

storage period, months - 3...6

The indicators of these properties depend on the scope of the solution and its composition.

Putty gypsum mixes

Putty mixtures are dispersed mixtures of non-water-resistant gypsum binders of B- or a-modifications, anhydrite or waterproof gypsum binders (gypsum-cement-pozzolanic or composite gypsum binders), fine and finely dispersed fillers and targeted chemical additives.

Such mixtures are intended for fine and finishing leveling of the surfaces of walls and ceilings; for the final preparation of concrete and plastered surfaces for painting or wallpapering; for facing and restoration works. They are used for sealing longitudinal and transverse joints between GKL and GVL during interior finishing work, as well as seams during the installation of gypsum tongue-and-groove boards. They have good adhesion to various materials and practically do not shrink. The advantage of gypsum putties is their rapid hardening, which allows further finishing work after several hours of hardening.

The most famous types of gypsum putty mixtures include: UNIFLOT; FUGENFULLER; FUGENFULLER Hydro; FUGENFULLER GW; FUGENFIT; FINISHING; UNIS GSH; GSH Slide; UNICE Bleek; R-16 MONOLITH; R-1 7 MONOLITH; GLIMS-Gypsum; PETRO-MIX SHG; ShGL; ShGS; SHGU; KREPS GKL and others.

Gypsum putty mixtures are characterized by the following properties:

hardened solution density, kg/m3 - 1100...1800;

compressive strength, MPa - 4...1 0;

tensile strength in bending, MPa - 2.5 ... 5;

storage period, months - 3...6

Dry gypsum mixes (mounting)

Mounting mixtures are mortar mixtures of non-waterproof gypsum binders of p- and a-modifications or waterproof gypsum binders (gypsum-cement-pozzolanic or composite gypsum binders) with a specially selected complex of chemical additives.

Such mixtures are used in the installation internal partitions from gypsum tongue-and-groove slabs; when facing internal surfaces with plasterboard and gypsum fiber sheets, as well as when arranging floor bases from gypsum fiber boards.

The most famous types of gypsum assembly mixtures include: PERLFIX, ("KNAUF"), GIPSOKONTAKT ("Bolars"), VOLMA installation (JSC GIPS, Volgograd), etc.

The main physical and technical characteristics of some types of gypsum assembly mixtures are as follows:

bulk density, kg / m 3 - 800 ... 950;

water-solid ratio - 0.4...0.6;

solution processing time, min. - 60...120;

hardened mortar density, kg/m3 - 1300...1350;

compressive strength, MPa - 4...7.5;

tensile strength in bending, MPa - 1.5...5;

adhesion strength, MPa - 0.3 ... 0.7;

storage period, months - 6

Dry gypsum floor mixes (levelling)

Dry mixes for floor installation are mortar mixes of non-waterproof gypsum binders a-modification, anhydrite, estrich gypsum or waterproof gypsum binders (gypsum-cement-pozzolanic or composite gypsum binders) and a special set of chemical additives to increase the plasticity of the mortar while reducing the water content.

The most well-known types of gypsum mixtures intended for the installation of floor bases include ATLAS SAM 200 mixtures, self-leveling composition Alfa-Pol C, Quick-hardening floor (“Prospectors”), SV-210 floor mixture (Bolars), etc.

As self-levelling compositions known dry mixes for self-leveling floors: Flissestrich FE 80, Flissestrich FE 50, Flissestrich FE 25, which are produced by Knauf enterprises. The hardened solutions from these mixtures have high strength and practically do not shrink.

The main physical and technical characteristics of some types of gypsum leveling mixtures for flooring are as follows:

bulk density, kg / m 3 - 600 ... 700;

water-solid ratio - 0.48...0.6;

solution processing time, min. - 60...120;

the density of the hardened solution, kg / m 3 - 1100 ... 1800;

compressive strength, MPa - 4...10;

tensile strength in bending, MPa-2.5,.,5;

adhesion strength, MPa - 0.3 ... 0.5;

storage period, months - 3...6

Raw materials

For the manufacture of SGS, the following basic materials and additives are used: gypsum binders grades G4-G7 according to GOST 125-79 (for plaster and putty mixtures in the production of finishing works):

high-strength gypsum grade not lower than I 3 according to GOST 125-79 (for high-strength putties and compositions for installation work, as well as in compositions for self-leveling floor screeds); waterproof gypsum binders according to TU 21 -0284757-1-90 (for dry gypsum mixtures used in rooms with wet and wet operating conditions, as well as for floor mixtures); anhydrite binders (from natural raw materials and industrial waste) according to TU21-0284747-1-90 (for plaster mixtures and leveling mixtures for flooring);

hydrated lime according to GOST 9179-77 (residue on sieve 02 up to 0.2% by weight). Humidity up to 0.5% by weight (in plaster compositions and in compositions of self-leveling mixtures for flooring).

Aggregates and fillers have a great influence on the properties of GHS. The choice of aggregate grain size is determined by the type of gypsum mixture: quartz and limestone sand are used with a fineness of up to 0.8 - 1.0 mm. When selecting aggregates, special attention is paid to the granulometric composition: there should be approximately the same ratio of aggregate fractions.

The GHS uses the following aggregates and fillers:

expanded perlite sand according to GOST 10832-91; residue on a sieve with a mesh size of 1.25 mm - less than 10% by weight. Bulk density - from 70 to 125 kg/m3; used in compositions of heat-insulating or lightweight plaster mixtures;

expanded vermiculite sand according to the current NTD;

quartz sands according to GOST 21 38-91, the residue on sieve No. 05 is less than 10% by weight. Moisture less than 0.5% by weight; used in the composition of plaster mixtures and in the composition of leveling mixtures for flooring;

mineral powder for asphalt mixes according to GOST 16557-78, the residue on the sieve No. 0315 is less than 10% by weight. Humidity is not more than 0.5% by weight; used in the composition of plaster and putty mixtures.

Chemical additives for gypsum mixtures must meet the requirements of GOST 24211-91. These include the following additives:

water-retaining based on cellulose ethers (methylcellulose brand MC-100 (Russia); ethyloxyethylcellulose, EOEC (Sweden); sodium salt of carboxymethylcellulose, (CMC), (Russia).

Based on cellulose esters (methylhydroxyethylcellulose, (MHEC), (Germany, USA); methylhydroxypropylcellulose (MHPC), (South Korea);

air-entraining anionic surfactants (Russia, Germany); olefin sulfonate (Germany);

thickening based on starch ether (Russia, Germany); based on hectorite clays (Italy);

plasticizing naphthalene-formaldehyde, for example C-3 (Russia); melamine-formaldehyde (Germany); polycarboxylate (Germany);

redispersion polymer powders: based on vinyl acetate copolymers (Germany, Switzerland, USA, France); based on styrene-butadiene latex (Germany); based on acrylate (Germany);

defoamers- additives, which are hydrocarbons and polyglycols on an inert carrier (amorphous silica).

In the manufacture of GHS, it is of great importance right choice additives that regulate the beginning and end of setting, especially intended for the production of plaster work. In this case, it is necessary to take into account not only the type of gypsum binder, but also the pH environment of the prepared gypsum mortar.

For a neutral environment of a gypsum mortar, citric acid, sodium citrate, polyphosphates, protein hydrolysates, gelatins - CMC (sodium salt of carboxymethylcellulose), adhesives of animal origin, a mixture of lignosulfonates can be effective setting retarders. However, it should be borne in mind, for example, that retardane, being an active gypsum setting retarder, is very well suited for putty compositions. At the same time, for plaster compositions, it is not effective enough, because. gives a short period between the beginning and the end of setting, which is undesirable in the production of plaster work.

For gypsum mortars with an alkaline environment, tartaric acid, as well as a retarder based on tartaric acid and plastretard, are effective retarders.

For slightly acidic environments, e.g. plaster solutions on the basis of a gypsum binder from phosphogypsum, hydrated lime and sodium tripolyphosphate are used as a retarder.

To achieve the required delay in the setting of the gypsum mortar, it is advisable to use a complex additive. A typical example is pla-stretard - a mixture of citric acid with polyphosphates and gelatin.

To reduce cracking and shrinkage deformations, cellulose fibers are introduced.

Putty, grout mixtures and gypsum adhesives differ from plaster compositions, both in their component composition and in its dispersion. A feature of these compositions is that building gypsum with a particle size of less than 0.1 mm is used as a binder, the filler is limestone, dolomite flour, chalk with a grain size of less than 0.1 mm. In this regard, the number of water-retaining additives increases to 0.5-0.8%, while in plaster compositions - 0.16-0.3%.

Of great importance in SSS, including SGS, are water-retaining additives based on cellulose ethers. Studies have shown that due to the weak intermolecular interaction with water molecules, these polymers have excellent water-holding capacity. Each polymer molecule can hold up to 20,000 water molecules. The energy of this interaction is comparable to the energy of evaporation and capillary diffusion into the substrate, which is an obstacle to the escape of water. In turn, this energy is somewhat less than the diffusion energy of water during cement hydration, which allows it to take this water.

In fact, the water in the solution is replaced by a homogeneous jelly-like solution of methylcellulose, in which particles of cement and aggregate are suspended. The high water-retaining capacity of such a system contributes to the complete hydration of the cement and allows the mortar to gain the required strength even with thin-layer application. After leaving the water, the polymer in the form of the thinnest film remains on the surfaces between the cement stone and the filler, without affecting the mechanical characteristics of the hardened mortar. Thus, the addition of a small amount (0.02-0.07%) of water-soluble cellulose ethers to cement-sand mixtures leads to a significant increase in open time and allows the solution to hydrate evenly throughout the volume, and also provides a significant increase in adhesion to the base and improvement surface quality. Similarly, the action of methylcellulose in gypsum mixtures.

Dispersion powders, which, unlike water-soluble cellulose derivatives, do not form solutions when mixed with water, but two-phase systems consisting of polymer particles (based on copolymers of vinyl acetate and ethylene, vinyl chloride, styrene acrylate, etc.) dispersed in water . The addition of these compositions to construction chemicals allows you to actively influence the characteristics of the final material and provides results that are unattainable using only traditional mineral binders. The first attempts to modify cement mixtures with polymers consisted of adding a vinyl acetate dispersion, known as PVA glue, to the mixing water. In gypsum mortars, this application turned out to be very effective, while in cement mortars (due to increased shrinkage from the use of PVA) they were quickly abandoned. The next step was the use of two-component compositions consisting of a cement-sand mixture prepared at the factory and a polymer dispersion supplied in liquid form, which are mixed at the construction site. Two-component solutions are still used, but the aqueous dispersion loses its properties when it freezes, therefore, in the cold season, its transportation and preparation of the working solution cause certain difficulties. The beginning of the production of one-component dry building mixtures dates back to 1953, when the specialists of the Wacker company (Germany) managed to obtain a dry redispersible powder, which, after mixing with water, forms a two-phase system that has the properties of the original polymer dispersion.

Dispersions differ from methylcellulose in their mechanism of action. As water is consumed, it concentrates in the pores cement stone and dispersion is concentrated there, forming “elastic bridges” that work in tension and bending incomparably better than cement. The combination of mineral and polymeric binders makes it possible to produce building chemistry products that have not only increased strength properties and improved adhesion (including to such “problematic” substrates as metal, wood, plastic, glazed tiles, etc.), but and controlled rheological (thixotropy, plasticity) and special (hydrophobicity, fluidity) characteristics. For example, leveling mortars for floors contain a combination of special dispersion additives with organic and synthetic plasticizers, the presence of which determines such specific properties of these materials as the ability to spread and the smoothness of the resulting surface. Dispersion modifiers, which are part of adhesive compositions for tile work, improve working conditions, prolong the “lifetime” of the closed solution and increase the thixotropy (the ability to thicken at rest and liquefy when mixed) of the material. They help increase adhesion to complex substrates.

The development of dry mix formulations is a complex and lengthy process that requires the participation of qualified personnel and the obligatory availability of a modern laboratory for research and testing samples of solutions from dry mixes, equipped with modern equipment.

State Unitary Enterprise "NIIMosstroy" develops the formulation of gypsum dry mixes according to the orders of enterprises, tests all types of dry building mixes, including certification ones. To this end, the laboratories of the institute are equipped with modern instruments and equipment, incl. for testing binders according to European standards. Besides. Certification Center NIIMosstroy certifies products and quality management systems.

Plaster mixtures in construction are used very widely. Such compositions can be used for interior walls, ceilings, facades, columns, etc. There are several types of such mixtures on the modern market. And one of the most popular varieties is plaster based on gypsum. Many companies produce such compositions. However, some brands of gypsum mixtures are, of course, the most popular among consumers.

What criteria are used to evaluate

When choosing gypsum plaster, first of all, you should pay attention to its characteristics such as:

maximum allowable layer thickness;

drying time;

base type;

Gypsum plasters are usually used only for finishing indoor surfaces. For facades, such compositions are not used. In most cases, manufacturers also recommend using such products only in dry rooms.

The best plasters

Most of the products of this type sold on the market today are of good quality. But still, the most popular gypsum plasters among consumers are:

"Rotband".

• "Gipswell".

  Bergauf.

  "Prospectors".

  "Eunice Teplon".

Plasters "Rotband"

Dry mixes on this brand belong to the group universal means. The composition of Rotband plasters, among other things, includes special additives designed to increase their adhesive properties. Also gypsum mixtures "Rotband" contain all sorts of natural impurities that determine their color. Depending on the manufacturer, such compositions can be:

• pink.

In this case, the pink Rotband plaster is considered the highest quality. Such mixtures are produced by the Knauf Gips Chelyabinsk and Knauf Gips Kolpino enterprises. White and gray gypsum plasters of this brand are produced in Krasnogorsk, the Krasnodar Territory and the Astrakhan Region. Such funds can also be considered of sufficient quality. However, when using them, you should still be a little more careful. White and gray plasters "Rotband" flow down the wall a little, as a result of which horizontal waves can form on the surfaces.

Consumer reviews

The advantages of Rotband plasters are primarily attributed by consumers to their plasticity, strength and the ability to achieve the smoothest possible surfaces. Working with such compositions, judging by the reviews, is very easy, and on the walls in the future, such a finish lasts as long as possible. Also, consumers consider the advantages of Rotband plasters, of course, their excellent adhesive qualities, as well as minimal shrinkage.

Some disadvantage of such gypsum mixtures, consumers consider not too long "survivability" of the solution. It is necessary to work with such plaster as quickly as possible or not to knead a very large amount of it at the same time. Also, consumers attribute a rather high cost to the disadvantages of Rotband.

Mixtures "Volma"

A feature of the plaster of this brand is considered primarily plasticity and the ability to "breathe". This mixture is produced by the domestic company Volma, founded back in the 40s. There are several types of this plaster on the market today, slightly different in composition:

"Volma-Sloy", designed for use in rooms with temperature fluctuations.

"Layer Titanium" and "Ultra", the most resistant to cracking.

"Canvas" with mineral additives that maximize adhesion.

"Plast" - universal, very plastic.

"Lux" - designed for work on foam concrete.

Also, this manufacturer produces gypsum dry building mixes intended for machine application: Gypsum-Active with additives that provide increased moisture resistance, and crack-resistant Gypsum-Active Extra.

Reviews about mixtures "Volma"

The most popular type of plaster of this brand among consumers is Volma Canvas. It is about this gypsum binder mixture that the Web has the best reviews. The advantages of Volma Holost formulations are primarily attributed by consumers to ease of application and versatility. This mixture, as noted by some masters, can be used to level walls, texturing under decorative plaster and even, for example, sculpting bricks.

The masters consider the main disadvantages of Volma Canvas to be too fast setting and the need for puttying after drying for a fine finish.

Dry building mixes with gypsum binder "Gipswell"

The compositions of this brand are a cheap analogue of "Rotband". Several varieties of such plasters are supplied to the market today. The most popular among the consumer is the Gipswell Osnovit mixture. Such plaster also comes in several series. For example, the mixture "Gipswell Found T25" can be applied to the walls with a layer of up to 8 cm. Also, this plaster is plastic.

In addition to the gypsum itself, the composition of "Gipswell Osnovit T25" includes additives that increase the "pot life" of the solution and plasticity. Like "Rotband", this plaster gives a very smooth surface and does not need additional puttying.

Consumer opinion about Gipswell

Good reviews about this plaster on the Web are available in the first place, due to the ease of application. The compositions of this brand, as noted by consumers, give a very high-quality finishing layer and at the same time are inexpensive. Low consumption is also considered an advantage of Gipswell building gypsum mixtures.

If the plaster on the surface needs to be applied in a thick layer, many consumers are advised to purchase this particular brand of T25. The finished finish in this case is guaranteed not to crack. Also, judging by the feedback from consumers, "Gipswell Found T 25" practically does not shrink. The advantages of this tool, many masters include the fact that the solution prepared with its use is able not to dry out for 1.5 hours.

Plaster "Bergauf": composition, description

The composition of gypsum-based mixtures from this manufacturer may include, in addition to the binder itself, the following components:

• quartz sand;

  mineral supplements;

  plasticizers.

The solution prepared from the Bergauf mixture hardens in about an hour. Additives make it plastic and easy to apply. Also, mixtures from this manufacturer have excellent adhesive properties.

Reviews of Bergauf blends

The main advantage of plasters of this brand, consumers consider their low cost. The price of Bergauf dry gypsum mixes, with their high quality, is often lower than for some similar compositions, even from domestic manufacturers.

Despite the fact that these plasters contain sand, which is noticeable, judging by consumer reviews, even with the naked eye, they give a finishing layer that is quite even and smooth.

Plaster "Prospectors"

The mixture of this brand is great for finishing all kinds of surfaces. The same quality layer when using them is obtained both on brick and on foam concrete. A special light component is added to the composition of the Starateli plaster, which can significantly reduce its consumption. Also, mixtures of this brand contain mineral components that provide rapid hardening.

It is believed that the Prospectors plaster is just great for applying on surfaces like under ceramic tiles, and just for wallpaper or painting. It is possible to apply dry mixes on a gypsum basis of this brand on the walls with a layer of up to 5 cm. The “life” of a solution prepared using the composition of this brand is 45 minutes.

What consumers think about Starateli plaster

Consumers consider the main advantage of the mixture of this brand to be a very low cost with good quality. Also, the advantages of plaster "Prospectors" masters include:

smoothness of the finished surface;

ease of application;

optimum setting time.

The craftsmen consider that some of the disadvantages of this brand are that large grains of sand sometimes come across in its composition. Therefore, when working with Prospectors plaster, you should be a little more careful. Sand grains can leave grooves on the surface. If they are not sealed immediately, the wall may subsequently have to be puttied.

Gypsum mixture "Eunice Teplon"

Plasters of this brand contain perlite, which reduces their setting time. A distinctive feature of the funds "Eunice Teplon" are light weight and maximum strength of the finished layer. Also, the plaster of this brand is able to additionally protect the premises in the house from the street cold.

The duration of the "life" solutions "Eunice" is approximately 50 minutes. You can apply them on the walls with a layer of up to 5 cm.

Consumer opinion

The main advantage of Eunice plasters is ease of application. Many consumers, judging by the reviews available on the Web, consider dry gypsum mixes of this brand to be just perfect for beginners. The Eunice Teplon solution is applied to the walls very easily. In addition, the finished finishing layer when using it does not require additional puttying.

Some disadvantage of Eunice mixtures, consumers consider the difficulty in preparing the solution. It is necessary to knead this plaster for a long time and carefully until all lumps are removed.

Instructions for use

For the most part, gypsum plasters are thus plastic. That is, working with them is quite easy. But of course, in order to get a beautiful durable finished finishing layer, when working with such compositions, all the required technologies should be observed.

Before starting plastering work, the surface must be cleaned of dirt, dust off it and primed in two layers. Next, you can start preparing the solution. At the same time, the amount of dry gypsum plaster mixture should be taken such that the finished composition could be fully used while it retains its "viability". This is necessary in order to avoid overspending the product, as well as damage to the container in which the solution was prepared.

Like any other mixtures, it is desirable to apply gypsum to the walls using the “beacons” technology. That is, first put the guide rails on the walls, and then level the solution using the rule.

Approximately 20 min. after application, it is desirable to level the gypsum plaster layer with a special paint float. To make the finished surface as neat as possible, after a few more hours it needs to be moistened with water and walked over it with a trowel.

Other mixtures: types and manufacturers

Of course, the most popular type of such compositions are plasters. But on the basis of gypsum, of course, other gypsum mixtures are also produced. For example, when decorating premises, the following types of compositions of this variety can be used:

• putties;
• assembly mixes;
• adhesives.

There are many brands of such products on the market. But the best manufacturers are those who produce the highest quality plaster. That is, it is primarily "Rotband", "Volma", "Eunice", etc.

Putties

This type of gypsum mixture is used for finishing the plaster layer. The advantages of such putties include, first of all, the smoothness of the finished surface, white color, setting speed. In addition to finishing, gypsum products of this variety can also be used for correction different kind surface defects before plastering.

Mounting mixes and glue

Compositions of this type have the same advantages as plasters or putties. That is, they seize very quickly and give white surface easily dyed. Such mixtures are used when cladding walls with gypsum boards or gypsum boards.